Slim Fan

ABSTRACT

A slim fan includes a housing, an impeller, and a stator unit. The housing includes a bottom board. The bottom board includes an inner face and an outer face. The bottom board includes at least one receiving space located between the inner face and the outer face. An impeller is rotatably mounted in the housing. A stator unit is mounted in the housing. The stator unit includes a circuit board, a coil unit, and at least one electronic element. The coil unit and the at least one electronic element are mounted on the circuit board. The at least one electronic element extends into the at least one receiving space.

CROSS REFERENCE TO RELATED APPLICATION

The application claims the benefit of Taiwan application serial No. 106136539, filed on Oct. 24, 2017, and the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a fan and, more particularly, to a slim fan.

2. Description of the Related Art

Generally, since electronic elements in electronic products generate heat during operation, many electronic products are equipped with heat dissipating fans for a long time. The heat dissipating fans provide a wind driving function to force air currents to flow for expelling the high temperature air inside the electronic products, increasing the heat dissipating efficiency during operation of the electronic products and thereby maintaining stable operation of the electronic products.

However, with the developing demands of thinning and high performances of electronic products, “thinning” is another aim in addition to fulfilling the heat dissipating demand of electronic products. Thus, the developing trends of many electronic products in recent years focus on how to reduce the axial height of the heat dissipating fans. Current heat dissipating fans generally include a housing, a stator unit mounted in the housing, and an impeller rotatably mounted in the housing. When it is desired to reduce the axial height of the overall heat dissipating fan, most designs aim in improvement to the structure of the stator unit.

With reference to FIG. 1, as an example, a conventional thin fan 9 includes a housing 91, a stator unit 92, and an impeller 93. The housing 91 includes a bottom board 911 and a shaft tube 912 connected to the bottom board 911. The stator unit 92 includes a circuit board 921 mounted around the shaft tube 912. The stator unit 92 further includes a plurality of coils 922 formed by windings. The coils 922 are mounted on and electrically connected to the circuit board 921. The impeller 93 includes a shaft 931 rotatably mounted in the shaft tube 912. The impeller 93 further includes a magnetic element 932 aligned with the coils 922. An embodiment similar to the thin fan 9 is disclosed in Taiwan Patent No. 1342098 entitled “Motor.”

Since at least one electronic element 923 (such as a driving element) is mounted to a lower face of the circuit board 921, the housing 91 requires a pad 913 annularly disposed around an outer periphery of the shaft tube 912 and connected to the bottom board 911, such that the circuit board 921 abuts the pad 913 when the circuit board 921 is mounted around the shaft tube 912. Furthermore, a gap G exists between the lower face of the circuit board 921 and the bottom board 911 for receiving the at least one electronic element 923. Thus, it is difficult to further reduce the axial height of the fan 9, and the structure of the housing 91 is complicated and is difficult to form.

Thus, improvement to the conventional thin fans is necessary.

SUMMARY OF THE INVENTION

To solve the above problems, the present invention provides a slim fan that is simplified in the structure of a housing to further reduce the axial height of the slim fan.

The present invention provides a slim fan to simplify the structure of the housing thereof to thereby increase convenience in manufacture of the housing and assembly of the slim fan.

When the terms “top”, “bottom”, “inner”, “outer”, “side”, and similar terms are used herein, it should be understood that these terms have reference only to the structure shown in the drawings as it would appear to a person viewing the drawings and are utilized only to facilitate describing the invention, rather than restricting the invention.

A slim fan according to the present invention includes a housing, an impeller, and a stator unit. The housing includes a bottom board. The bottom board includes an inner face and an outer face. The bottom board includes at least one receiving space located between the inner face and the outer face. An impeller is rotatably mounted in the housing. A stator unit is mounted in the housing. The stator unit includes a circuit board, a coil unit, and at least one electronic element. The coil unit and the at least one electronic element are mounted on the circuit board. The at least one electronic element extends into the at least one receiving space.

Thus, the slim fan according to the present invention is simplified in the structure of the housing to further reduce the axial height of the slim fan and to increase the convenience of manufacturing the housing and assembly of the slim fan.

In an example, before the stator unit and the housing are assembled, each of a maximum axial height of the bottom board in an axial direction of the impeller and a maximum axial height of the stator unit in the axial direction of the impeller is not larger than 1.1 mm. The sum of the maximum axial height of the bottom board and the maximum axial height of the stator unit is larger than 1.1 mm. This can be applied in mini-type heat dissipating fan technique.

In an example, after the stator unit and the housing are assembled, the stator unit and the bottom board have an assembled axial height not larger than 1.1 mm. This can be applied in mini-type heat dissipating fan technique.

In an example, the at least one receiving space is located within a maximum diametric range of the stator unit. This assures that the bottom board has a higher structural strength.

In an example, the coil unit is formed on the circuit board by etching or electrocasting. This can further reduce the maximum axial height of the stator unit.

In an example, the circuit board includes a plurality of grooves, and the coil unit extends into the plurality of grooves. This can reduce the maximum axial height of the stator unit.

In an example, the at least one receiving space includes a through-hole extending through the bottom board. This increases the manufacturing convenience of the bottom board and is helpful in reducing the operating temperature of the at least one electronic element and the axial height of the fan.

In an example, the at least one receiving space includes a first chamber and a second chamber, the at least one electronic element extends into the first chamber, and a spacer is mounted in the second chamber. This reduces the axial height and avoid exposure of the at least one electronic element.

In an example, a diametric range of the first chamber in a diametric direction of the impeller is smaller than a diametric range of the second chamber in the diametric direction of the impeller. This increases the operational convenience while assembling the spacer.

In an example, the spacer does not protrude beyond the outer face of the bottom board. This avoids an increase in the maximum axial height of the overall slim fan.

In an example, the at least one receiving space includes a blind hole in the bottom board. Thus, the bottom board has a better structural strength and is less likely to deform.

In an example, the impeller includes a hub and a plurality of blades. The plurality of blades is annularly disposed on an outer periphery of the hub. Each of the plurality of blades includes an inner edge and an outer edge. A blade rotational range is formed between the inner edges and the outer edges of the plurality of blades. The stator unit is not located within the blade rotational range in an axial direction of the impeller. Thus, the maximum axial height of the overall slim fan can be reduced while effectively avoiding damage to the stator unit resulting from collision with the plurality of blades.

The present invention will become clearer in light of the following detailed description of illustrative embodiments of this invention described in connection with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic cross sectional view of a conventional thin fan.

FIG. 2 is a diagrammatic, exploded, perspective view of a slim fan of a first embodiment according to the present invention.

FIG. 3 is a diagrammatic cross sectional view of the slim fan of the first embodiment according to the present invention.

FIG. 4 is a diagrammatic, top view of the slim fan of the first embodiment according to the present invention before attachment of a cover.

FIG. 5 is a diagrammatic, top view of a stator unit and a bottom board of the slim fan of the first embodiment according to the present invention.

FIG. 6 is a cross sectional view of a slim fan of a second embodiment according to the present invention.

FIG. 7 is a cross sectional view of a slim fan of a third embodiment according to the present invention.

FIG. 8 is a cross sectional view of a slim fan of a fourth embodiment according to the present invention.

FIG. 9 is a cross sectional view of a slim fan of a fifth embodiment according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 2 shows a slim fan of a first embodiment according to the present invention. In this non-restrictive embodiment, the slim fan is in the form of a blower type fan. The slim fan of this embodiment includes a housing 1, an impeller 2 mounted in the housing 1, and a stator unit 3 mounted in the housing 1.

With reference to FIGS. 2 and 3, the housing 1 is a hollow housing capable of introducing air into and out of the hollow housing. In this embodiment, the housing 1 includes a bottom board 11, a sidewall 12, and a cover 13. The bottom board 11 includes an inner face 11 a and an outer face 11 b. The sidewall 12 is coupled to the bottom board 11. The cover 13 is connected to the sidewall 12 and faces the inner face 11 a of the bottom board 11. Thus, a space for receiving other members is defined between the bottom board 11, the sidewall 12, and the cover 13. The bottom board 11 includes at least one receiving space S located between the inner face 11 a and the outer face 11 b. Furthermore, the housing 1 includes a shaft coupling portion 14 mounted on the bottom board 11 and protruding from the inner face 11 a of the bottom board 11. The shaft coupling portion 14 can be integrally formed with or detachably coupled to the bottom board 11.

The impeller 2 includes a shaft 21, a hub 22, a plurality of blades 23, and a magnetic element 24. The shaft 21 is connected to the hub 22 and is rotatably mounted to the shaft coupling portion 14 of the housing 1. The plurality of blades 23 is annularly disposed on an outer periphery of the hub 22. The magnetic element 24 is mounted to an inner periphery of the hub 22. Each of the plurality of blades 23 includes an inner edge 231 and an outer edge 232. A blade rotational range R (see FIG. 4) is formed between the inner edges 231 and the outer edges 232 of the plurality of blades 23.

The stator unit 3 includes a circuit board 31, a coil unit 32, and at least one electronic element 33 (such as a driving element or a sensor element). The coil unit 32 and the at least one electronic element 33 are mounted on the circuit board 31. The circuit board 31 can be mounted around the shaft coupling portion 14. The coil unit 32 faces the magnetic element 24. The at least one electronic element 33 extends into the at least one receiving space S of the bottom board 11 but does not protrude beyond the outer face 11 b of the bottom board 11. Preferably, all electronic elements 33 are received in the at least one receiving space S.

Specifically, the circuit board 31 includes a first surface 31 a and a second surface 31 b opposite to the first surface 31 a. The circuit board 31 can be coupled with the shaft coupling portion 14 by press fitting, and the first surface 31 a of the circuit board 31 abuts the inner face 11 a of the bottom board 11 of the housing 1. Alternatively, the circuit board 31 is mounted around the shaft coupling portion 14 by loose fitting, and the first surface 31 a of the circuit board 31 is bonded to the inner face 11 a of the bottom board 11 of the housing 1 by an adhesive (such as a gum or a glue) or hot melting. In a case that the bottom board 11 of the housing 1 is made of an insulating material, the circuit board 31 can be directly bonded to the inner face 11 a of the circuit board 11 by the inner surface 11 a. In another case that the bottom board 11 of the housing 1 is made of a non-insulating material, an insulating plate (not shown) can be disposed on the first surface 31 a of the circuit board 31, and the circuit board 31 can be indirectly bonded to the inner face 11 a of the bottom board 11 via the insulating plate.

It is noted that before the stator unit 3 and the housing 1 are assembled, the bottom board 11 has a maximum axial height h1 in an axial direction of the impeller 2, and the maximum axial height h1 of the bottom board 11 in the axial direction of the impeller 2 is not larger than 1.1 mm. Furthermore, the stator unit 3 (the overall height of a combination including the circuit board 31, the coil unit 32, and the at least one electronic element 33) includes a maximum axial height h2 in the axial direction of the impeller 2, and the maximum axial height h2 of the stator unit 3 in the axial direction of the impeller 2 is not larger than 1.1 mm. Furthermore, after the stator unit 3 and the housing 1 are assembled, the stator unit 3 and the bottom board 11 have an assembled axial height H1 not larger than 1.1 mm.

After assembly of the slim fan according to the present invention, the at least one electronic element 33 of the stator unit 3 extends into the at least one receiving space S of the bottom board 11 but does not protrude beyond the outer face 11 b of the bottom board 11, such that the assembled axial height H1 can be smaller than the sum of the maximum axial height hl of the bottom board 11 and the maximum axial height h2 of the stator unit 3. Thus, the maximum axial height H2 of the overall slim fan is reduced while simplifying the structure of the housing 1 (without the need of the pad in the prior art). The overall slim fan is more light and more thin and is easy to manufacture and assemble. As a result, the slim fan according to the present invention can be used in the heat dissipating technique in which the sum of the maximum axial height h1 and the maximum axial height h2 is larger than 1.1 mm and in which the assembled axial height H1 is preferably not larger than 1.1 mm.

Furthermore, with reference to FIGS. 3 and 4, the stator unit 3 is not located within the blade rotational range R in the axial direction of the impeller 2, such that the plurality of blades 23 of the impeller 2 can be closer to the inner surface 11 a of the bottom board 11, which is helpful in reducing the maximum axial height 112 of the overall slim fan. Furthermore, damage to the stator unit 3 resulting from collision with the plurality of blades 23 can be effectively avoided.

Furthermore, in a non-restrictive example, the at least one receiving space S can include a through-hole extending through the bottom board 11 to increase the manufacturing convenience of the bottom board 11. Furthermore, a portion of the air currents can flow through the at least one receiving space S into the housing 1 during rotation of the impeller 2 and can directly flow toward the at least one electronic element 33 of the stator unit 3.

Thus, the operating temperature of the at least one electronic element 33 and the axial height of the fan can be reduced. The coil unit 32 of the stator 3 can be formed on the circuit board 31 by etching or electrocasting to further reduce the maximum axial height h2 of the stator unit 3.

Furthermore, with reference to FIGS. 3 and 5, the at least one receiving space S can be located within a maximum diametric range of the stator unit 3, assuring that the bottom board 11 can have a higher structural strength.

FIG. 6 shows a slim fan of a second embodiment according to the present invention. The second embodiment according to the present invention is substantially the same as the first embodiment except for the at least one receiving space S.

Specifically, in this embodiment, the at least one receiving space S is still in the form of a through-hole extending through the bottom board 11. Nevertheless, the at least one receiving space S includes a first chamber S1 and a second chamber S2 communicating with the first chamber S1. The first chamber S1 is adjacent to the inner face 11 a of the bottom board 11, and the second chamber S2 is adjacent to the outer face 11 b of the bottom board 11. A diametric range of the first chamber S1 in a diametric direction of the impeller 2 is smaller than a diametric range of the second chamber S2 in the diametric direction of the impeller 2. The at least one electronic element 33 of the stator unit 3 extends into the first chamber S1. The slim fan further includes a spacer 4 mounted in the second chamber S2. The spacer 4 can be a label and preferably does not protrude beyond the outer face 11 b of the bottom board 11, such that the slim fan provides an identifying effect without increasing the maximum axial height H2 of the overall slim fan while avoiding exposure of the at least one electronic element 33.

FIG. 7 shows a slim fan of a third embodiment according to the present invention. The third embodiment according to the present invention is substantially the same as the first embodiment except that the at least one receiving space S of the third embodiment is a blind hole in the bottom board 11, such that the bottom board 11 has a better structural strength and is less likely to deform.

FIG. 8 shows a slim fan of a fourth embodiment according to the present invention. The fourth embodiment according to the present invention is substantially the same as the first embodiment except that the coil unit 32 of the stator unit 3 of the fourth embodiment can be of a coreless winding type or a type having silicon steel plates with windings. Since the coil unit 32 of these types has a larger axial height, the circuit board 31 of the stator unit 3 can include a plurality of grooves 311, and the coil unit 32 can extend into the plurality of grooves 311. Alternatively, a portion of the electronic elements 33 can be received in the plurality of grooves 311 to reduce the maximum axial height h2.

FIG. 9 shows a slim fan of a fifth embodiment according to the present invention. This embodiment shows a slim fan according to the present invention in the form of an axial flow type fan. Specifically, the slim fan of this embodiment includes a housing 5, an impeller 6 mounted in the housing 5, and a stator unit 7 mounted in the housing 5.

The housing 5 includes a bottom board 51, a sidewall 52, and a plurality of ribs 53. The bottom board 51 includes an inner face 51 a and an outer face 51 b opposite to the inner face 51 a. The bottom board 51 is mounted inside the sidewall 52. The plurality of ribs 53 connects the bottom board 51 to the sidewall 52. The bottom board 51 includes at least one receiving space S located between the inner face 51 a and the outer face 51 b. Furthermore, the housing 5 includes a shaft coupling portion 54 mounted on the bottom board 51 and protruding from the inner face 51 a of the bottom board 51.

The impeller 6 includes a shaft 61, a hub 62, a plurality of blades 63, and a magnetic element 64. The shaft 61 is connected to the hub 62 and is rotatably mounted to the shaft coupling portion 54 of the housing 5. The plurality of blades 63 is annularly disposed on an outer periphery of the hub 62. The magnetic element 64 is mounted to an inner periphery of the hub 62.

The stator unit 7 includes a circuit board 71, a coil unit 72, and at least one electronic element 73 (such as a driving element or a sensor element). The coil unit 72 and the at least one electronic element 73 are mounted on the circuit board 71. The circuit board 71 can be mounted around the shaft coupling portion 54. The coil unit 72 faces the magnetic element 64. The at least one electronic element 73 extends into the at least one receiving space S of the bottom board 51 but does not protrude beyond the outer face 51 b of the bottom board 51.

It is noted that, in this embodiment, the housing 5 further includes a limiting portion 55 on the inner face 51 a of the bottom board 51, such that the circuit board 71 mounted around the shaft coupling portion 54 can be restrained within the limiting portion 55. Nevertheless, the maximum axial height hl of the bottom board 51 does not include the thickness of the limiting portion 55.

By the arrangement of the above structure, after assembly of the slim fan of this embodiment, the at least one electronic element 73 of the stator unit 7 extends into the at least one receiving space S of the bottom board 51 of the housing 5 but does not protrude beyond the outer face 51 b of the bottom board 51, such that the assembled axial height H1 of the stator unit 7 and the bottom board 51 can be smaller than the sum of the maximum axial height hl of the bottom board 51 and the maximum axial height h2 of the stator unit 7, thereby reducing the maximum axial height H2 of the overall slim fan.

In view of the foregoing, the slim fan according to the present invention is simplified in the structure of the housing 1, 5 to further reduce the axial height of the slim fan and to increase the convenience of manufacturing the housing 1, 5 and assembly of the slim fan.

Although the invention has been described in detail with reference to its presently preferable embodiments, it will be understood by one of ordinary skill in the art that various modifications can be made without departing from the spirit and the scope of the invention, as set forth in the appended claims. 

What is claimed is:
 1. A slim fan comprising: a housing including a bottom board, wherein the bottom board includes an inner face and an outer face, wherein the bottom board includes at least one receiving space located between the inner face and the outer face; an impeller rotatably mounted in the housing; and a stator unit mounted in the housing, wherein the stator unit includes a circuit board, a coil unit, and at least one electronic element, wherein the coil unit and the at least one electronic element are mounted on the circuit board, and wherein the at least one electronic element extends into the at least one receiving space.
 2. The slim fan as claimed in claim 1, wherein before the stator unit and the housing are assembled, each of a maximum axial height of the bottom board in an axial direction of the impeller and a maximum axial height of the stator unit in the axial direction of the impeller is not larger than 1.1 mm, and wherein a sum of the maximum axial height of the bottom board and the maximum axial height of the stator unit is larger than 1.1 mm.
 3. The slim fan as claimed in claim 2, wherein after the stator unit and the housing are assembled, the stator unit and the bottom board have an assembled axial height not larger than 1.1 mm.
 4. The slim fan as claimed in claim 1, wherein the at least one receiving space is located within a maximum diametric range of the stator unit.
 5. The slim fan as claimed in claim 1, wherein the coil unit is formed on the circuit board by etching or electrocasting.
 6. The slim fan as claimed in claim 1, wherein the circuit board includes a plurality of grooves, and wherein the coil unit extends into the plurality of grooves.
 7. The slim fan as claimed in claim 1, wherein the at least one receiving space includes a through-hole extending through the bottom board.
 8. The slim fan as claimed in claim 7, wherein the at least one receiving space includes a first chamber and a second chamber, wherein the at least one electronic element extends into the first chamber, and wherein a spacer is mounted in the second chamber.
 9. The slim fan as claimed in claim 8, wherein a diametric range of the first chamber in a diametric direction of the impeller is smaller than a diametric range of the second chamber in the diametric direction of the impeller.
 10. The slim fan as claimed in claim 8, wherein the spacer does not protrude beyond the outer face of the bottom board.
 11. The slim fan as claimed in claim 1, wherein the at least one receiving space includes a blind hole in the bottom board.
 12. The slim fan as claimed in claim 1, wherein the impeller includes a hub and a plurality of blades, wherein the plurality of blades is annularly disposed on an outer periphery of the hub, wherein each of the plurality of blades includes an inner edge and an outer edge, wherein a blade rotational range is formed between the inner edges and the outer edges of the plurality of blades, and wherein the stator unit is not located within the blade rotational range in an axial direction of the impeller. 